This application claims the priority of German Application 19916675.7, filed Apr. 14, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to an apparatus for adjusting the relative or phase angle of a camshaft.
DE 197 26 300 A1 discloses an apparatus in which the impeller and the housing wheel have arranged between them a spring element that holds the impeller in a basic position. As a result, the impeller cannot move even when there is no oil pressure applied, and it is ensured that noise will no longer occur when the internal combustion engine is started and that the desired valve timings will be set even for the exhaust valve.
In this known arrangement, the housing wheel and the impeller each have recesses in which the spring element is arranged in order to ensure a certain guidance for the latter. On one hand, however, the guidance provided for the spring element is inadequate owing to the shallowness of the recess and, on the other hand, it is extremely expensive in terms of manufacture to produce the recess in the housing wheel. If the depth of the recess were increased, which would be advantageous for the guidance of the spring element, these difficulties in terms of manufacture would be increased.
With regard to the general prior art as regards apparatuses for adjusting the relative angle of camshafts, attention is furthermore drawn to EP 0 821 138 A1, EP 0 801 212 A1, DE 39 07 077 C2, DE 41 08 111 A1, DE 44 02 586 A1, DE 196 30 403 A1 and DE 196 54 926 A1.
An object of the present invention is to provide an apparatus for adjusting the angle of a camshaft relative to the crankshaft driving the camshaft. The apparatus retains the advantages as regards the adoption of the basic position but, at the same time, can be produced in a simple manner and with little outlay on machinery.
According to the invention, this object is achieved by opening the pocket-like recess of each projection in the axial direction.
By virtue of the fact that, according to the invention, the pocket-like recess of the at least one projection is open in the axial direction, the housing wheel can be produced economically by sintering, rendering a large amount of finish machining work unnecessary. Moreover, the spring elements can also be installed easily in the cavity between the impeller and the housing wheel.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.